Ignition system for engine

ABSTRACT

An ignition system, particularly for an internal combustion engine having a piston slidably disposed within a cylinder and coacting with the housing to define a combustion chamber therebetween. An ignition device is mounted on the housing for igniting a fuel-air mixture within the combustion chamber. The ignition device includes a high intensity light source within a sealed compartment, which compartment is isolated from the combustion chamber by an intermediate lens. The light source is preferably partially surrounded by a reflector so that, upon energization of the light, the radiant energy is transmitted through the lens which causes the light energy to be concentrated at a point located within the combustion chamber for causing ignition of the fuel-air mixture.

United States Patent Gamell [451 Jan. 21, 1975 IGNITION SYSTEM FOR ENGINE [75] Inventor: Joseph A. Gamell, Kalamazoo,

Mich.

[73] Assignee: Joseph Gamell Ind., Inc.,

Kalamazoo, Mich.

[22] Filed: Dec. 10, 1973 [21] Appl. No.: 423,251

Primary Examiner-Manuel A. Antonakas Assistant Examiner-James W. Cranson Attorney, Agent, or Firm-Woodhams, Blanchard & Flynn [57] ABSTRACT An ignition system, particularly for an internal ,combustion engine having a piston slidably disposed within a cylinder and coacting with the housing to define a combustion chamber therebetween. An ignition device is mounted on the housing for igniting a fuel-air mixture within the combustion chamber. The ignition device includes a high intensity light source within a sealed compartment, which compartment is isolated from the combustion chamber by an intermediate lens. The light source is preferably partially surrounded by a reflector so that, upon cnergization of the light, the radiant energy is transmitted through the lens which causes the light energy to be concentrated at a point located within the combustion chamber for causing ignition of the fuel-air mixture.

IGNITION SYSTEM FOR ENGINE FIELD OF THE INVENTION This invention relates to an improved ignition device, particularly for use with a combustion engine, for igniting a combustible gas.

BACKGROUND OF THE INVENTION As is well known, the fuel-air mixture located within the combustion chamber of a conventional internal combustion engine has, for many years, been conventionally ignited by means of sparking devices, such as a spark plug. The use of spark plugs has proven successful and advantageous for use in internal combustion engines as evident by their continued and extensive use over an extremely long period of time. However, those familiar with the problems associated with engine combustion have long been aware that the combustion achieved utilizing a spark plug does result in several characteristics and/or problems which make the use of spark plugs somewhat disadvantageous, either due to the problems caused by the spark plugs themselves or by the limitations which they impose on the desired operation of the engine.

For example, the use of spark plugs requires a periodic maintenance of the engine, as by requiring that the spark plugs be replaced after a selected operational period, since the plugs corrode and often become fouled with deposits. Thus, the plugs do not function in the most efficient manner and sometimes cease to function at all. A further problem which has existed in many situations due to the use of spark plugs is the problem of preignition of the fuel-air mixture due either to the retained heat of the electrode or the static electricity contained thereon.

The use of spark plugs also limits the combustion characteristics, as by requiring the use of richer fuel-air mixtures within the combustion chamber. Since spark plugs have proven to be ineffective for igniting extremely lean fuel-air mixtures, this thus requires that the engine be supplied with a richer fuel-air mixture, which thus results in the engine consuming greater quantities of fuel. Further, supplying the engine with rich fuel-air mixtures also results in less complete combustion so that undesired pollutants, such as unburned hydrocarbons and the like, are often discharged into the surrounding atmosphere.

Still a further problem associated with the use of spark plugs results from the positioning of the spark plug relative to the combustion chamber. Since the spark generated by the plug is created between a pair of closely spaced electrodes, which electrodes are secured to the body of the spark plug, the electrodes must necessarily be positioned closely adjacent the wall of the combustion chamber so as to prevent the spark plug from projecting substantially into the combustion chamber. By positioning the electrodes adjacent the wall of the combustion chamber, this thus limits the type of flame propagation which can be obtained within the combustion chamber and accordingly often results in nonuniform combustion.

Accordingly, it is an object of the present invention to provide an improved ignition device, particularly suitable for use in association with the combustion chamber ofan engine, which ignition device overcomes the above-mentioned disadvantages. Thus, it is an object of the present invention to provide:

1. An ignition device which provides a concentrated quantity of heat within a combustion chamber for igniting a combustible gas, such as a fuel-air mixture, which quantity of heat is generated by a radiant energy source, such as a light source, located externally of the combustion chamber.

2. An ignition device, as aforesaid, wherein the light source comprises a high energy light, such as a strobe light, which generates sufficient radiant energy which can be concentrated at the desired point within the combustion chamber for forming a concentrated quantity of heat to result in ignition of the combustible gas.

3. An ignition device, as aforesaid, wherein a lens isolates the light source from the combustion chamber while causing the radiant energy generated by the light source to be concentrated at a selected point within the combustion chamber.

4. An ignition device, as aforesaid, which enables the heat concentration point to be located a substantial distance from the walls of the combustion chamber, such as by permitting the point to be located substantially at the center of the combustion chamber, to provide for more uniform and efficient combustion of the fuel-air mixture.

5. An ignition device, as aforesaid, wherein the ignition device is adjustable, such as by moving the lens relative to the light source, to enable the point of heat concentration to be selectively varied relative to the combustion chamber.

6. An ignition device, as aforesaid, wherein the light source is preferably partially surrounded by a reflector for causing all of the radiant energy to be directed through the lens for concentration at the selected point, the light and reflector preferably being disposed within a closed compartment which is maintained under a vacuum.

7. An ignition device, as aforesaid, which can effectively ignite the combustible mixture located within the combustion chamber, even when said combustible mixture is rather lean, whereby the engine will consume lesser quantities of fuel and will result in emission of less pollutants.

8. An ignition device, as aforesaid, which can be made to operate over extremely long periods of time without requiring periodic maintenance or repair, which eliminates the problem of preignition, and which permits a more efficient and economical generation of power by the engine.

Other objects and purposes of the present invention will be apparent to persons acquainted with systems of this general type upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary cross-sectional view illustrating a combustion chamber of an engine having an igni tion device associated therewith.

FIG. 2 is a diagram of a typical electrical timing system which can be associated wilth the ignition device of FIG. I for causing intermittent energization thereof according to a desired time sequence.

Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words upwardly," downwardly," rightwardly" and leftwardly" will refer to directions in the drawings to which reference is made. The words inwardly and outwardly" will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof and words of similar import.

SUMMARY OF THE INVENTION The objects and purposes of the present invention are met by providing an ignition device for association with an engine, particularly an internal combustion engine of the multi-cylinder type as conventionally utilized on vehicles. The ignition device is mounted for coaction with each cylinder of the engine and includes a compartment which is disposed adjacent the combustion chamber but is sealed from communication with the combustion chamber by means of an intermediate lens. A light source, particularly a high intensity light such as a strobe light, is disposed within the compartment and is energized by a suitable electrical system. The light source, which is preferably surrounded by a reflector, results in generation of radiant energy which is transmitted through the compartment and through the lens into the combustion chamber. The lens causes the radiant energy to be concentrated at a selected point within the combustion chamber, whereupon the concentration of the radiant energy at this selected point results in a sufficient concentration of heat to cause ignition of the combustible mixture located within the chamber. The ignition point at which the concentrated heat is located can be adjusted relative to the configuration of the chamber.

DETAILED DESCRIPTION Referring to the drawings, FIG. 1 illustrates therein a portion of an internal combustion engine 11 which has an ignition device 12 according to the present invention associated therewith. The ignition device 12 is intermittently energized in a selected time sequence by means of a suitable electrical control system 13 which is schematically illustrated in FIG. 2. While FIG. 1 illustrates only one cylinder of an internal combustion engine, it will be appreciated that the present invention is equally applicable and is in fact intended for use with conventional multi-cylinder engines, whereupon the combustion chamber associated with each cylinder will have an ignition device 12 associated therewith.

The engine 11 includes a conventional housing or engine block 16 containing an elongated cylinder 17 having a conventional piston 18 slidably disposed therein. The piston 18 is connected to a conventional crank shaft by means of an intermediate connecting rod (not shown). A combustion chamber 19 is defined within the cylinder 17 between the end wall 21 thereof and the opposed end surface 22 as formed on the piston 18. The combustion chamber is supplied with a combustible gas, particularly a fuel-air mixture, through a suitable inlet port having a conventional intake valve 23 associated therewith, and the exhaust gases are suitably discharged through a further port having a conventional exhaust valve 24 associated therewith. The valves 23 and 24 are moved between open and closed positions in a selected timed sequence with respect to one another by means of a conventional valve timing structure (not shown).

The engine structure as described above is well known, and thus further description or illustration thereof is not believed necessary.

Considering now the ignition device 12, same includes a cup-like support housing 26 provided with an elongated bore 27 therein, which bore is closed at its upper end. The support member 26 is provided with an externally threaded sleeve portion 28 on the lower end thereof, which sleeve portion is threadably engaged with an internally threaded opening 29 formed in the engine block 16. Since the opening 29 also communicates with the combustion chamber 19, this results in the bore 27 also communicating with the combustion chamber 19.

The support housing 26 is provided with a light source 31 positioned within the upper end of the bore 27, which light source comprises a high intensity light. such as a strobe lamp (i.e., a strobotron However. the light source 31 may comprise any other suitable high intensity light, such as a halogen lamp, a quartz tungsten lamp or a mercury lamp. The light source 31 is supported within the bore 27 by an electrically conductive support member or buss bar 32, which member rigidly supports the light source 31 within the bore and extends externally of the support housing 26. Suitable electrical conduits 33 and 34 are connected to the light source 31 for energizing same, with the conduit 33 being interconnected to the light source through the buss bar 32. A further electrical conduit 36 is connected between the light source 31 and the support housing 26, which conduit 36 functions as a ground,

The light source 31 is preferably partially surrounded by means of a curved reflection 37. The reflector 37 is provided with an interior reflective surface 38 thereon for causing the radiant energy generated by the light source 31 to be directed longitudinally downwardly along the bore 27 towards the combustion chamber 19.

The light source 31 is isolated from the combustion chamber 19 by means of an intermediate converging lens 39 which is located within the bore 27 adjacent the lower end thereof. The lens 39 has the annular peripheral edge thereof mounted in sealed relationship on an adjustable mounting ring 41 which is externally threaded and is disposed in threaded engagement with the internal threads 42 provided on the sleeve portion 28. The lens 39, due to its sealed relationship with the mounting ring 41, results in the formation of a closed compartment 43 containing therein the light source 31 and the reflector 38. The compartment 43 is preferably initially evacuated to create a partial vacuum therein.

The lens 39 is suitably shaped, as by having a lower convex surface, so as to result in the light rays generated by the light source 31 being effectively concentrated at a point 44 as the light rays pass from the chamber 43 through the lens 39 into the combustion chamber 19. The concentration of the light rays at the point 44 results in a sufficient concentration of radiant energy to result in a substantially instantaneous accumulation of heat to thus cause ignition of the combustible mixture contained within the chamber 19. The location of the point 44 relative to the chamber 19 can be suitably varied, and similarly the effective concentration of the light rays at the point 44 can also be maximized, by rotatably adjusting the ring 44 relative to the sleeve portion 28, thereby moving the lens 39 axially of the bore 27 as desired. Further, the complete ignition device 12 can also be adjustably positioned relative to the engine block 16 by initially rotating the support housing 26 relative to the engine block 16 to thus partially withdraw the threaded sleeve portion 28 from the threaded opening 29. If necessary, a suitable shim or other spacer can be positioned between the lower surface of the housing 26 and the upper surface of block 16.

The intermittent energization of the light source 31 is controlled by the electrical control circuit 13 which, as illustrated in FIG. 2, is somewhat conventional and includes therein the same basic components associated with the ignition system of an automotive engine. The control system 13 includes an ignition coil 46 associated with movable points or contacts 47 which intermittently and rapidly open and close for controlling the timed ignition of the combustible gas associated with the cylinders of the engine. The points 47 have a conventional condensor 48 associated therewith. The one end of the coil 46 is connected to the electrical conduit 33, whereas the other end of the coil'46 is connected to a battery 49 by means of a conventional keyoperated switch 51. The coil 46 is also connected to the other electrical conduit 34 through an intermediate power supply 52, which power supply may include a conventional distributor in the form of a rotary switching device for causing sequential ignition of the cylinders of amulti-cylinder engine in the desired sequence.

OPERATION The operation of the ignition system according to the present invention is believed apparent from the description given above. However, a brief description of the operation is set forth hereinafter to insure a complete understanding of the invention.

During the conventional operation of an engine, the intake and exhaust valves 23 and 24 are periodically opened and closed in a timed sequence with respect to one another, thereby permitting a fresh fuel-air mixture to be supplied into the combustion chamber 19 via the intake valve 23 while permitting the exhaust gases from the previous combustion to exit via the valve 24. When it is desired to ignite the combustible mixture within the chamber 19 to cause the piston 18 to move downwardly through a power stroke, the timing provided by the control circuit 13 causes electrical energy to be supplied to the light source 31 via the conductors 33 and 34. The light source 31 is momentarily energized which results in the generation of a large quantity of light rays within the chamber 43. Due to the presence of the reflector 37, the light rays are transmitted downwardly through the bore 27 onto the lens 39. The light rays are then transmitted through the lens 39 which causes the light rays to be effectively concentrated at the point 44. This rapid and substantially instantaneous concentration of light rays at the point 44 results in an instantaneous accumulation of heat, thus creating a hot spot at the point 44 which is sufficient to cause ignition of the molecules associated with the fuel-air mixture in the immediate vicinity of the point 44. This ignition of the fuel-air mixture at the point 44 then propagates throughout the chamber 19, thus causing a complete combustion of the fuel-air mixture and resulting in expansion thereof to provide for a powered downward movement of the piston 18. Since the point 44 of initial ignition is located a substantial distance from the wall of the combustion chamber 19, and in fact can be located centrally of the combustion chamber if desired,

the combustion occurs in a very uniform manner since the combustion can propagate outwardly in substantially all directions with respect to the point 44 to thus result in rapid and uniform combustion of substantially all of the fuel-air mixture. This results in very efficient and rapid combustion to thus minimize the discharge of undesired pollutants. Further. due to the extreme concentration of heat energy at the point 44, the fuel-air mixture within the combustion chamber can be effectively ignited even though the mixture is lean. that is. contains a minimum of fuel.

Further, since the complete ignition device 12 can he axially adjusted relative to the cylinder 17, and inasmuch as the lens 39 can also be adjusted axially relative to the light source 31, this thus enables the ignition point 44 to be selectively varied as desired relative to the geometrical configuration of the combustion chamber 19.

While the ignition device of the present invention has been described above for use in conjunction with a conventional internal combustion engine. which engine may be of a single cylinder or a multi-cylinder type. nevertheless the ignition device of the present invention is also equally applicable to numerous other types of combustion engines. For example, the ignition device 12 of the present invention could be utilized to replace the conventional glow plug which is used for igniting the combustible mixture associated with a deisel engine. Further, due to the rather instantaneous concentration of heat at the point of ignition by means of the device according to the present invention, same is also applicable for causing ignition of the combustible mixture associated with ajet engine. For use in ajet engine, the ignition could be facilitated by utilizing a plurality of spaced ignition devices for causing ignition of the combustible mixture at several spaced points within the combustion chamber.

Further, the ignition device of the present invention can also be used to ignite a combustible gas associated with numerous other devices, such as a furnace or the like.

While the invention as described above results in intermittent energization of the light source, the present invention also encompasses an ignition system wherein the light source is continuously energized. In such a system, an intermittently openablc shutter could be positioned between the light source and the ignition point.

With respect to the control circuit 13, it maintains a continuous potential on the light source 31 which is just below the ionization level thereof. The power supply 52 thus results in imposition of a potential pulse on the light source which is sufficient to result in ionization thereof. The power supply 52 is of conventional construction, and may include circuitry for converting DC. current to A.C. current, with a step-up of the A.C. current being achieved, and the A.C. current then being reconverted to DC. current for supply to the light source.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In an internal combustion engine having housing means defining a cylinder therein and a piston slidably disposed within said cylinder, said piston and said cylinder cooperating to define a combustion chamber, and an ignition device coacting with said combustion chamher for igniting a fuel-air mixture therein, the improvement wherein said ignition device comprises:

a support housing fixed to said housing means and defining a compartment therein; an energizable light source positioned within said compartment for generating radiant energy, said light source consisting of a high intensity lamp;

electrical conduit means connected to said lamp for energizing same; and

means coacting between said compartment and said combustion chamber for permitting transmission of radiant energy from said compartment to said combustion chamber and for causing concentration of said radiant energy at a selected location within said combustion chamber to cause ignition of the fuel-air mixture.

2. An internal combustion engine according to claim 1, further including reflector means positioned within said compartment in the vicinity of said light source for reflecting the radiant energy generated thereby in a direction toward said combustion chamber.

3. An engine according to claim 2, wherein said lamp is a strobotron.

4. An internal combustion engine according to claim 4, further including reflector means positioned within said compartment in the vicinity of said light source for reflecting the radiant energy generated thereby in a direction toward said combustion chamber.

7. An engine according to claim 6, wherein said compartment is maintained under a partial vacuum.

8. An internal combustion engine according to claim 1, further including means operatively connected to said light source for causing intermittent energization thereof.

9. An engine according to claim 1, wherein said housing means has a threaded opening formed therein and communicating with said combustion chamber. and said support housing comprising a sleevelike member closed at one end and open at the other end thereof. said other end being threadably engaged with said 

1. In an internal combustion engine having housing means defining a cylinder therein and a piston slidably disposed within said cylinder, said piston and said cylinder cooperating to define a combustion chamber, and an ignition device coacting with said combustion chamber for igniting a fuel-air mixture therein, the improvement wherein said ignition device comprises: a support housing fixed to said housing means and defining a compartment therein; an energizable light source positioned within said compartment for generating radiant energy, said light source consisting of a high intensity lamp; electrical conduit means connected to said lamp for energizing same; and means coacting between said compartment and said combustion chamber for permitting transmission of radiant energy from said compartment to said combustion chamber and for causing concentration of said radiant energy at a selected location within said combustion chamber to cause ignition of the fue1air mixture.
 2. An internal combustion engine according to claim 1, further including reflector means positioned within said compartment in the vicinity of said light source for reflecting the radiant energy generated thereby in a direction toward said combustion chamber.
 3. An engine according to claim 2, wherein said lamp is a strobotron.
 4. An internal combustion engine according to claim 1, wherein said coacting means comprises lens means for sealingly isolating said compartment from said combustion chamber while permitting transmission of radiant energy therethrough and concentration of said radiant energy at said location.
 5. An internal combustion engine according to claim 4, further including means mounting said lens means for adjusting the position thereof relative to said light source.
 6. An internal combustion engine according to claim 4, further including reflector means positioned within said compartment in the vicinity of said light source for reflecting the radiant energy generated thereby in a direction toward said combustion chamber.
 7. An engine according to claim 6, wherein said compartment is maintained under a partial vacuum.
 8. An internal combustion engine according to claim 1, further including means operatively connected to said light source for causing intermittent energization thereof.
 9. An engine according to claim 1, wherein said housing means has a threaded opening formed therein and communicating with said combustion chamber, and said suppOrt housing comprising a sleevelike member closed at one end and open at the other end thereof, said other end being threadably engaged with said threaded opening. 